1. Technical Field
The present invention relates to semiconductor device fabrication and, more particularly, to merged fins in the source and drain regions of fin-based field effect transistors.
2. Description of the Related Art
When forming replacement metal gate fin field effect transistors (FinFETs), the portions of the fins in the source and drain regions are often merged to form a single conductive terminal. A gate spacer is formed, protecting the fins in the area under the gate, and the fins outside the gate spacer are epitaxially grown until neighboring fins come into contact with one another.
However, because the fins display both <110> and <100> crystalline surfaces, simple epitaxial growth of the existing fins may cause defects, particularly in growth from <110> surfaces. Furthermore, uncontrolled epitaxial growth is effective at partially merging fins, but it can be difficult to control and suppress that merge in desired locations.